I finally got the ecu out and the 2 plus pulled through into the engine bay as 1 or 2 of you good guys stated-now I am seeing better what you are talking about.

So,
Q1. ECU harness- a sprout off the harness goes to trans it appears from above - with 3 wires a Blue, a Purple and a Purple/black stripe (or close to a purple) - I've been reading and in some cases the speedometer requires some wires to work I think related to Vss as I recall- however, I believe I have a speedo cable going to the gauge that comes out the drivers side firewall about 3" below the drivers side main harness connector to the firewall, a little towards the engine side of this main connector and may not need these 3 wires as I am going to forgo TCC for now do to expected limited driving. (I sorta understand this issue now from your help here, so ignore the TCC needs pls) - Can you pls tell me if this is correct and the speedo only needs the "cable" to work?? - (this cable runs under the booster and down to the drivers side frame and looks like to trans)

Q2. There is a ground wire in the ECU harnass (with 1 wire light brown and 1 Black/gray stripe - do I need this for something?

Q3. ECU harness has 1 orange like wire in its own wrap with a connector on the end which connects to a wire goinng to the POS side of the Battery cable terminal- can you tell me what this is for and if needed?

Q4. ECU harness-there is a plastic vacuum line with a rubber boot that was connected to the carb, Can you tell me what this was for and if needed?

Q5. Cruise control "harness" - I disconnected the vacuum hose to the white connector next to another white connector with a 2 prong connector with 2 gray on 1 side and 1 light brown on the other. I took it off and then saw it was not part of the "cruise harness" and don't remember which way it went on. Can you tell me what this is for, if it's needed and which way it goes on, as it looks like the hold together thing on the connector was previously broke off. Alsom there is a connector to the steering column harness underneath that may be related to the cruise but not part of the harness that I can pull out?? is his true?

thanks for your help, although I've spent many hours on numerous threads, after a point in time it all mushes together and it's hard to go back and identify each spot where you saw a relevent bit of info, even though I copy them and save them in a Word doc. I have reviewed all I saved but need this help
thanks in advance - feel free to pick 1 of the Q1-Q5 questions as I don't expect any one person to spend time to answer all.

 

Read
https://www.thirdgen.org/forums/ltx-...p-3rd-gen.html

1.No wires to trans for VSS if you have a speedo drive .I would leave the wires in place so you can control the TCC at a later date

3.Most likely the ECM power wire, not needed with ECM gone.( good to keep if you want battery power for something later on

4.Vac line to inside car.Required to operate your A/c vent positions

5.Are you removing the CC?

 

thanks vetteoz
yes CC removing in process but didn't pull it thru yet, Q5
Keeping a/c and heater
also Q7. there is a plug by the ecu which i had to disconnect as part of the ecu harness under the pass dash- Is this going to the port on the other side of the console to plug in the diagnostics?? If so can I just tape it under the dash and leave the port?
Q8. Is there any "wiring" associated with the TV cable (finanlly figured out it means throttle valve or Kickdown cable-correct me if i'm wrong)) Worried about this and because of no funds I need to adapt a good Oldsmobile carb to work somehow-Do you guys know how they rivet or crimp the little "rods" that hold the cables on the throttle what you call it where the throttle cable is attached to the carb? The carb has a hole but I somehow need to attach a "rod to attach the TV cable to it

 

What colors are the wires?

 

can't get to the car now but it is a big plug, likely 8-12 wirres in it and was an offshhoot from the main ecu harness (right by the 2 plugs for the ecu under the dash)
also, not a wire question but I'll ask anyway-I need to use the existing mechanical fuel pump on the car but want to eliminate the return line rusted tubing-However, the little tube on the bottom of the pump is rusted to **** and part broke off when I pulled of the rubber hose-question is, is there any pressure in that return line coming from the pump and what would you suggest I do to close it up? Have no money or access to special equip-just a half *** solution needed
or would it be ok to use a mech pump from an old bib-block i have (didn't have a return line in 69

 

There are 9 wires in the plug (various colors) which was just 3-5 inches from the 2 ecu plugs. Oh regarding Q4 - that vac line went to a "box" like sensor I think that has a metal from and about 1 1/2 " wide and 3 1/2" long, It holds the other end of the vac line that went to the carb and takes a 3 prong round sensor like connector too.

Q4 maybe- I got out the CC and I see a vac line I marked a couple weeks ago the comes out the firewall by the pass side head, as part of a 1/2" tape wrapped wire harness- I believe this was connected to a vac line that came from the "cruise" connections in the engine bay- maybe this is the A/C vac line??

any help on the other issues I have would be appreciated
thx

 

https://www.thirdgen.org/forums/post...08-post33.html
https://www.thirdgen.org/forums/post...75-post40.html
https://www.thirdgen.org/forums/post...096-post7.html

A SBC pump maybe , BBC pump is different as I recall

 

Thanks for the replies-these are open questions I have
Q2. There is a ground wire in the ECU harnass (with 1 wire light brown and 1 Black/gray stripe - do I need this for something?

Q3. ECU harness has 1 orange like wire in its own wrap with a connector on the end which connects to a wire goinng to the POS side of the Battery cable terminal- can you tell me what this is for and if needed?

Q5. Cruise control "harness" - I disconnected the vacuum hose to the white connector next to another white connector with a 2 prong connector with 2 gray on 1 side and 1 light brown on the other. I took it off and then saw it was not part of the "cruise harness" and don't remember which way it went on. Can you tell me what this is for, if it's needed and which way it goes on, as it looks like the hold together thing on the connector was previously broke off. Alsom there is a connector to the steering column harness underneath that may be related to the cruise but not part of the harness that I can pull out?? is his true?

thanks for your help

 

Q2 If a wire comes from the ECM plug ( like a ground ) it is most likely redundant
Q3 I already answered
Q5 where is the "white connector next to another white connector"
Put a pic up

You realize you could just look at a 85 ECM wiring diagram like this one

http://www.chevythunder.com/1985_tpi_ecm.htm

and work out the ECM wiring yourself??????

 

Sorry Vetteoz, you've been very helpful to me and YOU ARE RIGHT! - I've been lazy in not looking at the diagrams, partly due to my 60yr old eysight as I did take a look at these but not a good reader of these. I also haven't posted a picture yet as I tried to put another person's picture in 1 I sent but didn't work-I'll figure it out, but

on the brake pedal there are connectors behind it- on the 1 side of the bracket was a white connector which had the cruise hose plugging in it- on the other side is the 2 wire connector I mention above - the other connector under the dah 1 wire goes to the steering column harness and MUST be to the cruise button in the turn sig lever-hope I haven't offended you, as I do have tons of work to do on this car and sometimes get lazy- The owner had the new car hebought z-batered using the "protector" company and they sprayed undercoating all over the engine bay, shock towers air con hoses, water bottle, etc, and I get sick when I look at it and ponder how I'm gonna get this **** off and ever make the engine bay look decent.

I did buy all available books on ebay for cheap, including the 85 gm shop manual with 3 inches of goodness that came with the car (that one is the most confusing one I've found) and read all on them pretty much-not the big one however-

your help is greatly appreciated
tom

 

Should mention that up top.

Consider all newbies as 17yo's not prepared to do any work and expecting instant answers unless otherwise informed

This link
http://92b4crs.tripod.com/86wiring/86wiringindex.html

has many factory circuit diagrams for non engine systems; for '86 but yours should be similar.

Like this for the CC electrics
http://92b4crs.tripod.com/86wiring/dia-pics/34-0.jpg

and the CC vac
http://92b4crs.tripod.com/86wiring/dia-pics/34-1.jpg

This pdf
http://www.eecis.udel.edu/~davis/z28...ody-wiring.pdf

has clearer details of the ECM pinouts. Pg 6 has a listing of the ECM connector terminals and colors

This link
http://www.berlinetta.info/C100.htm
has the firewall connector details

 

thanks-I'll view tomorrow-(I wish I was 17 again however) - have a good night
tom